When I first read this, I thought it was a good treatment of a Fantasy Campaign. Not as good as some of TSR's stuff, but it is still good. You can still run a campaign with it in any Fantasy Roleplaying system. And it is chock full of information!
In order to run it, it's best ran in GURPS, with AD&D 2nd Edition next. The Campaign is set on the [i:]Magical World of Yrth[/i:], which a Banestorm had brought several medieval cultures together on one continent, not to mention races. The races all had their interesting take, some are given the same treatment, others are not.
But if you are looking for a good campaign to run that is unique to all the rest, I suggest GURPS Fantasy, or now -- GURPS [i:]Banestorm[/i:].
I actually read it cover to cover even though most people don't usually read RPG sourcebooks all the way trough. I remember it being interesting as a setting, but my friends and I only ever used the new races and creatures and imagined our own fantasy setting.